1. Field of the Invention
The present invention relates to an adaptive headlight system of a vehicle, and more particularly to an adaptive front light system (AFLS) having high heat-dissipation efficiency, which increases heat-dissipation efficiency of a light emitting diode (LED) to improve durability in a headlight, which uses the LED as a light source and has a variable illumination angle according to conditions.
2. Description of Related Art
In general, headlights mounted on a vehicle have fixed illumination angle, and thus always illuminate the road ahead of the vehicle regardless of the driving conditions.
Consequently, the headlights of a vehicle running along a curved road can disturb an oncoming driver's view of the vehicle on the opposite lane (hereinafter, referred to as “oncoming vehicle”), and the driver himself/herself cannot properly secure clear visibility of the driving curved road so that the driver's safety is often jeopardized or endangered.
In order to cope with this situation, there has recently been developed a device that the headlights move in the left or right direction depending on the angle at which the driver turns a steering wheel in order to secure the proper visibility of the driver at night and prevent glaring headlights of the oncoming vehicle.
Furthermore, a vehicle is experiencing a nose-up phenomenon that the front portion of the vehicle is instantaneously raised at the fast acceleration and a nose-down phenomenon that the front portion of the vehicle is instantaneously lowered because of the hard braking. Due to these characteristics of the vehicle, the focus of the headlight can be located above or below the normal position at a moment, which is responsible for the glare of the oncoming vehicle or the driver's poor visibility.
FIG. 1 is a schematic view illustrating the heat dissipation structure of an adaptive front light system of the prior art.
As illustrated in FIG. 1, a reflector 20 is mounted in a lamp housing 10, the interior of which is sealed, so as to cause light to be reflected to travel forward the motor vehicle. As illustrated, the reflector 20 is provided with a light source 30 which emits light and a light emitting diode (LED) is frequently used as the light source 30 these days. The LED can be operated with low power and thus provides higher luminous efficiency than a bulb type with a high intensity of illumination. Further, the LED has a high degree of freedom in lamp design due to a smaller size compared with the bulb type, and has a semi-permanent lifespan only if the generated heat can be smoothly cooled down.
However, since the light source 30 using the LED generates a great deal of heat, the luminous efficiency is abruptly lowered without any proper means for the heat dissipation, and thus results in reducing the lifespan. For this reason, the light source 30 can be formed with a heat sink 40 as illustrated in FIG. 1 such that the generated heat from the light source 30 can be dissipated through the heat sink.
Here, the reflector 20 is adapted to rotate around a rotational axle 21 in leftward/rightward direction or in upward/downward direction. This is because the illumination angle of the headlight changes depending on the driving conditions of the vehicle.
For reference, an adaptive front light system (AFLS) refers to a system that adjusts the illumination angle of the headlight in a manner such that the reflector 20 rotates in the left and right direction according to the steering angle or upward and downward direction according to the height of the front portion of the vehicle.
However, since a heat dissipation structure is mounted inside the sealed lamp housing 10 in the adaptive headlight system of the prior art as above mentioned, the generated heat from the light source 30 cannot be properly dissipated outside via the heat sink 40 and is accumulated inside. Accordingly, the heat dissipation performance of the light source 30 gets worse. In detail, since the lamp housing 10 must be sealed to prevent moisture and dust from outside and the reflector 20 is adapted to rotate, the heat sink 40 cannot be installed outside the lamp housing 10 and should move together with the reflector 20. As such, the heat is not properly dissipated through the heat sink 40.
Particularly, this problem becomes more serious when a plurality of LEDs are installed in one lamp housing 10 in order to adjust luminous intensity of the headlight to the level of a high intensity discharge (HID) lamp.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.